Switching sign

Coherent sign switching in multiyear trends of microbial plankton.

Since the 1990s, phytoplankton biomass on the continental shelf of Nova Scotia and in the Labrador Sea has undergone sustained changes in the spring and fall, which are accompanied by changes in bacterioplankton that are dampened in amplitude but coherent in the direction of change. A reversal of trend in biomass change, so-called sign switching, occurs both in time and in space. Thus, whenever...

Time-varying/Sign-switching Risk Perception on Foreign Exchange Markets

In this paper we analyze the consequences of considering risk-augmented speci cations of the relationship between spot and forward rates. Previous parametric speci cations such as the GARCH-M provided disappointing results possibly due to the high degree of persistence of the estimated process for conditional volatility. We propose a more exible semiparametric approach where a nonparametric est...

Natural Selection: Sign, Sign, Everywhere a Sign

Natural selection is an important factor influencing variation in the human genome, but most genetic studies of natural selection have focused on variants with unknown phenotypic associations. This trend is changing. New studies are rapidly revealing the effects of natural selection on genetic variants of known or likely functional importance.

[Article] Switching the sign of Josephson current through Aharonov-Bohm interferometry

Sign switching behavior of cross-county interest rate correlations: Theory and Evidence

This paper considers the well established empirical fact that conditional correlations among cross-country interest rates switch signs. Switching implies an alternation of coupling and decoupling of global bond markets over time. This evidence is robust to alternative estimation schemes. Here we use a seminonparametric (SNP) model with a BEKK-GARCH variance function to estimate conditional seco...